Today's communication networks provide transport of voice, video, and data to both residential and commercial customers, with more and more of those customers being connected by fiber optic cables. In these communication networks, information is transmitted from one location to another by sending pulses of light through the fiber optic cables. Fiber optic transmission provides several advantages over electrical transmission techniques, such as increased bandwidth over distance with lower losses and maintenance.
Designers and installers of fiber optic networks are often confronted with significant space constraints that restrict the design of the network. In particular, terminations of fiber optic cabling (e.g., between the service provider and customer) require a dedicated space to accommodate and protect the fiber optic terminations. In some instances, the space available for a termination point may be limited to relatively small cabinets, data centers, and storage area networks. These small spaces are sometimes ill-suited to accommodate the high number of fiber optic terminations associated with modern, high-bandwidth networks. Consequently, network designers are constantly seeking ways to optimize space-efficiency.
High density fiber optic cassette systems have evolved as one solution to provide space-efficient fiber optic terminations. Fiber optic cassettes are standardized modules having a number of ports that are complementary to a standardized endpoint structure of fiber optic cables. These ports provide a plug-and-socket functionality that allows an installer to easily effectuate multiple terminations in an efficient, organized manner. Fiber optic cassettes may be mounted in a high-density optical distribution frame. These optical distribution frames have a number of internal mounting walls, each of the walls having tracks, so that one of the fiber optic cassettes can be secured to two of the mounting walls.
U.S. Pat. No. 6,591,051 to Solheid (hereinafter “Solheid”), which is incorporated by reference herein in its entirety, and U.S. Pat. No. 7,416,349 to Kramer (hereinafter “Kramer”), which is incorporated by reference herein in its entirety, describe examples of a high-density fiber optic distribution systems. Solheid describes a fiber distribution frame that is configured for the mounting of a number of modular fiber termination blocks thereto. The fiber termination blocks are enclosures that accommodate a number of fiber optic terminations. Each fiber optic termination block includes a number of regularly spaced apart mounting walls that are configured for the mounting of a number of fiber optic modules thereto. See, e.g., Solheid, FIG. 5 (depicting a fiber termination block 101 with a number of walls (unlabeled) and sliding adaptor modules 116 mounted to the walls); FIGS. 22-24 (depicting various perspectives of a wall 400 that is provided in the fiber optic termination block). Solheid describes an adaptor module that is configured to slidably mate with the walls of the fiber optic termination block. This is made possible by a track and rail system in which rails of the adaptor module engage with and slide into corresponding tracks that are provided on the mounting walls. The tracks are oriented at an oblique angle relative to the bottom of the fiber optic termination block such that the adaptor modules slide along a tilted angle. See, e.g., Solheid, FIGS. 29, 31 (depicting an adaptor module 316 being slid into the rails of a wall (unlabeled) along an angle G that is oblique relative to the bottom of the fiber optic termination block).
U.S. Pat. No. 8,417,074 to Nhep (hereinafter “Nhep”), which is incorporated by reference herein in its entirety, describes an example of a rear enclosure that is compatible with the adaptor module described by Solheid and Kramer. See, e.g., Nhep, FIGS. 4-9 (depicting rear module 36 that attaches to an adaptor block 56). The enclosure attaches to the adaptor module and provides an area for optical circuitry, e.g., splitters, multiplexers, attenuators, etc., to be stored and secured. This optical circuitry can be connected to some or all of the standardized fiber optic connectors that are disposed on the adaptor module.